Antenna



May 21, 1 94-6. D L HINGS 2,400,551

ANTENNA Filed May 3, 1944 Patented May 21, 1946 OFFICE ANTENNA Donald L. Hings, Ottawa, Ontario, Canada Application May 3, 1944, Serial No. 533,862 In Canada April 24, 1944 4 Claims.

My invention relates in general to electrical radio frequency circuits and more particularly to an antenna arranged to be mounted upon vehicles and other moving objects such as airplanes and boats.

An object of my invention is to reduce the required head clearance for vehicles and yet obtain high radiating efliciency.

Another object of my invention is to increase aerial capacity and Q, that is the ability of the antenna to respond to resonance and to permit a greater radio frequency energy to be taken from the output circuit of the radio frequency source and thereby prevent overloading of the transmitter components.

Another object of my invention is to prevent detuning effects from trees, neighbouring objects of all kinds which are common with high impedance antennas.

Another object of my invention is to present a sloping antenna surface to impact with overhead structures or objects for both forward and backward travel of the moving vehicle.

Another object of my invention is to obtain a maximum counter-poise effect from the mounting of my antenna on the vehicle, airplane or boat.

Another object of my invention is to provide a current conducting means for inter-connecting the loaded end of the antenna with the ground or common point of the radio frequency source to enable a greater Q to be obtained and bonding the current conducting means to the counterpoise or mass of the vehicle, boat or airplane.

Other objects and a fuller understanding of my invention may be had by referring to the following description and claims, taken in con junction with the accompanying drawing in which:

Figure 1 is a side elevation of a vehicle upon which my invention may be mounted;

Figure 2 illustrates the mounting of my invention upon a passenger vehicle;

Figure 3 is an illustration showing my antenna being mounted upon an airplane.

Figure 4 shows my invention being mounted upon a boat.

With reference to Figure 1 the vehicle upon which my antenna l5 may be mounted is provided with an all metal body I ll having a substantially flat top II. The forward end l6 of the antenna is supported by an anchoring means I3 suitably connected to the forward end of the top of the body ill of the vehicle. The rear end ll of the antenna is fastened to an insulating memher l8, which in turn is connected by means of a rod l9 and an anchoring means It to the rear end of the top ll of the vehicle. Any suitable means may be employed to connect the anchoring means l4 to the top of the vehicle and the rod l9 may also be of any suitable construction and may include a bendable element such as a stranded wire ca e as well as a rod. The antenna is preferably of the tapering bendable type such for example as commonly known as a whip aerial. The anchoring means I3 is insulated from the top of the vehicle such as illustrated by the insulating member or plate 20. The radio frequency source l2 has an output terminal 2| and a ground terminal 22. The output terminal 2! is connected to the anchoring means l3 and to the front end It of the antenna. The anchoring means 14 is electrically connected to the top ll of the vehicle. In my antenna a considerable amount of current passes and in some cases the top of the vehicle may have a relatively high resistance to the flow of current and in order to provide a low resistance path for the current I employ a low resistance conductor 23 for interconnecting the anchoring means M to the ground terminal 22 of the radio frequency source. The low resistance conductor 23 may be bonded at intervals to the top of the vehicle such as illustrated by the bond connections 24. The body of the vehicle represents a mass or counter-poise and is a ground to the radiation system, and the ground is designated by the ground symbol 25.

In radio frequency systems of medium and low frequency types the antenna resonant periods exceed the length of the conveyance many times. Thus for maximum radiation efliciency it is impossible in most cases for moving vehicles, boats and airplanes to have an antenna that Will ex ceed a fraction of the antenna resonant period. With a relatively short antenna which represents a capacitance to ground, the voltage will become increasingly high and to obtain eflicient radiation with low clearance and not have excessive voltage the capacity must be increased on the end of the antenna. In my invention I provide for giving maximum voltage at the end of the antenna even with low clearance by anchoring the rear end H to the body through the insulating member IS, the rod l9 and the anchoring means It. I find from actual practice that the insulating material should preferably have a high dielectric constant. The end I! of the antenna where it is connected to the insulating member I8 is substantially one-half as high as the maximum point of the intermediate portion of the antenna from the top of the vehicle. Also it is to be observed that the distance between the highest point of the antenna and the top of the vehicle is substantially equal to the distance between the two anchoring means 13 and M. In other words for best efiiciency, I need as much antenna height as I can obtain directly opposite from the center of the mass, as well as as much length of the antenna as I can obtain for the spacing between the insulating member i8 substantially one-half as high above the top of the vehicle as the highest point of the antenna 45.

The insulating member l8 represents a capacity loading reactance and to obtain maximum efficiency in my antenna circuit, the length of the insulating member l8 will alter inversely with the length of the aerial. The length of the insulating member [8 aids in regulating the field pattern. For example if the insulating member I8 is too short the field will be concentrated to the rear of the vehicle and of too long the current reduction due to insumcient loading will reduce the over-all pattern.

In Figure 2 I illustrate my antenna being mounted upon the passenger vehicle in which like reference characters correspond to those shown in Figure 1. The operation of the antenna on apassenger vehicle is exactly as that described in Figure 1. For stream-lined vehicles having a relatively long sloping back the anchoring means l3 may be mounted in a region of the rear window in which case the antenna would be totally confined to the rear of the vehicle.

In Figure 3 I illustrated my antenna as being mounted on an airplane fuselage in which case the fuselage of the airplane represents the conducting mass or counter-poise that is equivalent to the top of the vehicle truck body l0, and like reference characters represent parts corresponding to those in Figure 1.

In Figure 4 my invention is shown as being mounted upon a boat and like reference characters correspond to those in Figure 1. The counter-poise in the boat may be provided by employing the metal top of the cabin or any other conducting surface or conducting matting which may be provided thereon. The matting may also be provided on the flooring of the deck. The matting on top of the cabin and the matting on the deck of the boat may be electrically interconnected and both may be connected to the water for ground. One end of the matting is connected to the anchoring means M and the other end is connected to the ground terminal 22. The operation of the antenna with respect to its mounting on the boat and airplane is substantially the same as shown on the mounting on the vehicle in Figure 1.

Although I have shown and described my i vention with a certain degree of particularity, it is understood that changes may be made therein without departing from the spirit of the invention which are included within the scope of claims hereinafter set forth.

I claim as my invention:

1. A transmitting antenna arranged to be spaced from a radio frequency conductive mass and energized from a source of radio frequency having first and second terminals with the first terminal at a higher radio frequency potential than the second terminal, said second terminal being electrically connected to said mass, said antenna comprising first anchoring means insulated from said mass and connected to said first terminal of the radio frequency source, second anchoring means spaced from said first anchoring means and electrically connected to said mass, radiating means extending between said first and second anchoring means, said radiating means including a radiating member and a conducting rod, said radiating member having a first and a second end with an intermediate portion therebetween, conducting means for electrically connecting said first end to the first anchoring means, said conducting rod extending between said second end of the radiating member and said second anchoring means and being conductively connected to the mass, and insulating means between the said second end of the radiating member and the conducting rod, whereby maximum voltage may be developed at the said second end of the radiating memher, the said second end of the radiating member being spaced from the mass whereby the lines of force of the electrostatic energy emanating from the second end clear the mass when radiating toward the intermediate portion.

2. A transmitting antenna arranged to be spaced from a radio frequency conductive mass and energized from a source of radio frequency having first and second terminals with the first terminal at a higner radio frequency potential than the second terminal, said second terminal being electrically connected to said mass, said antenna comprising first anchoring means insulated from said mass and connected to said first terminal of the radio frequency source, second anchoring means spaced less than onequarter wave length from said first anchoring means and electrically connected to said mass, radiating means extending between said first and second anchoring means, said radiating means including a whip aerial and a conducting rod, said whip aerial having a first and a second end with a bowed portion therebetween, conducting means for electrically connecting said first end to the first anchoring means, said conducting rod extending between said second end of the whip aerial and said second anchoring means and being conductively connected to the mass, and insulating means between the said second end of the ship aerial and the conducting rod whereby maximum voltage may be developed at the said second end of the whip aerial, the second end of the whip aerial being spaced from the mass, whereby the lines of force of the electrostatic energy emanating from the second end clear the mass when radiating toward the bowed portion.

3. A transmitting antenna arranged to be spaced from a radio frequency conductive mass and energized from a source of radio frequency having first and second terminals with the first terminal at a higher radio frequency potential than the second terminal, said second terminal being electrically connected to said mass, said antenna comprising first anchoring means insulated from said mass and connected to said first terminal of the radio frequency source, second anchoring means spaced from said first anchoring means and electrically connected to said mass, radiating means extending between said first and second anchoring means, said radiating means including a radiating member and a conducting rod, said radiating member having a first and a second end with an intermediate portion therebetween, conducting means for electrically connecting said first end to the first anchoring means, said conducting rod extending between said second end of the radiating member and said second anchoring means and being conductively connected to the mass, and insulating means between the said second end of the radiatin member and the conducting rod, whereby maximum voltage may be developed at the said second end, the distance between said insulating means and said mass being at least one-half the distance between the said intermediate portion and said mass.

4. A transmitting antenna arranged to be spaced from a radio frequency conductive mass and energized from a source of radio frequency having first and second terminals with the first terminal at a higher radio frequency potential than the second terminal, said second terminal being electrically connected to said mass, said antenna comprising first anchoring means insulated from said mass and connected to said first terminal of the radio frequency source, second anchoring means spaced less than onequarter wave length from said first anchoring means and electrically connected to said mass. radiating mean extending between said first and second anchoring means, said radiating means including a whip aerial and a conducting rod, said whip aerial having a first and a second end with a bowed portion therebetween, conducting means for electrically connecting said first end to the first anchoring means, said conducting rod extending between said second end of the whip aerial and said second anchoring means and being conductively connected to the mass, and insulating means between the said second end of the whip aerial and the conducting rod, whereby maximum voltage may be developed at the said second end, the distance between said insulating means and said mass being at least one-half the distance between the said bowed portion and the said mass.

DONALD L. I-IINGS. 

